Needle and hub assembly for automatic injector

ABSTRACT

A needle and hub assembly for an automatic injector and a method for making the needle and hub assembly. The needle and hub assembly comprises a cap or skirt, a forward surface of which is interposed between and reinforced by first and second engaged hub portions. A needle is received in a contiguous channel formed in the two hub portions. The method for making the assembly comprises molding the first hub portion, placing the cap over the first hub portion, inserting the needle into a channel in the first hub portion, and then overmolding or otherwise forming the second hub portion on the exterior of the cap such that it is engaged with the first hub portion. An assembly created by this “two-shot” process can be used to seal a relatively large opening, and supports the needle more effectively than a conventional assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of U.S. patent application Ser. No.10/690,987 filed on Oct. 23, 2003, which is a continuation-in-part ofU.S. patent application Ser. Nos. 09/897,422, filed on Jul. 3, 2001 nowU.S. Pat. No. 6,641,561, and 09/972,202, filed on Oct. 9, 2001 now U.S.Pat. No. 6,770,052. Those two applications claim priority to U.S.Provisional Nos. 60/238,458, 60/238,448, and 60/238,447, all filed onOct. 10, 2000. The contents of all of those applications areincorporated by reference herein in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to drug delivery devices. Moreparticularly, the present invention relates to needle and hub assembliesfor automatic injection devices.

2. Description of Related Art

Many types of syringes and other injection devices are used in themedical device arts. Typical syringes, for example, use a hollow needleto deliver a medicament subcutaneously, intramuscularly, orintravenously to a patient. The needle is usually connected to theportion of the syringe that holds the medicament by a hub assembly. Thehub assembly secures the needle and also supports it.

An automatic injector is a type of injection device that enablesintramuscular (IM) or subcutaneous administration a dose of medicament.In the typical automatic injector, a cartridge carries the dose ofmedicament and is connected to a needle assembly. The cartridge andneedle assembly are contained within a housing, which also carries anactuation assembly. When the actuation assembly is activated, the needleis caused to penetrate and protrude from the housing and the medicamentis caused to be injected into the patient. Thus, automatic injectorsallow for quick and simple IM injection of a medicament in emergencysituations without the need for measuring dosages. Additionally,automatic injectors are convenient for self-administration ofmedicament, because the user does not see the needle before actuation ofthe device, and there is no need to manually force the needle into thepatient.

There are three main types of automatic injectors. A first type is thatwhich carries its medicament mixed in liquid form. A second type ofautomatic injector, called a “wet/dry” automatic injector, has twoseparate compartments and carries its medicament in the form of twocomponents, a dry component and a liquid component. When the actuationassembly is activated, structure within the cartridge of the automaticinjector forces the dry and liquid components of the medicament to mix.A third type of automatic injector, called a “wet/wet” automaticinjector, has two separate compartments and carries its medicament inthe form of two liquid components. The wet/wet automatic injectorincludes structure within the cartridge that may force the twocomponents to mix when the actuation assembly is activated or theautomatic injector may deliver the fluid consecutively.

In one common arrangement of an automatic injector, one of themedicament compartments is directly adjacent to the needle assembly.During manufacture, the compartment adjacent to the needle assembly isfilled with a medicament component and the needle assembly is installedover the opening in the compartment to seal it. The needle assemblyincludes a needle hub and the needle itself. With this sort ofarrangement, it is beneficial if the opening in the cartridge and thecompartment is as wide as possible, because wide openings allow foreasier filling of the compartment with the medicament, especially whenthe medicament or component is in the form of a dry powder or alyophilized tablet. However, the size of the opening is limited inpractice because it is difficult to make a needle assembly that can sealthe compartment well and support the needle adequately.

SUMMARY OF THE INVENTION

One aspect of the invention relates to a needle and hub assembly for aninjection device. The needle and hub assembly comprises a cap, a firsthub portion, a needle, and a second hub portion engaged with the firsthub portion. The cap has an engaging portion constructed and arranged toengage an exterior surface of a cartridge and a needle-supportingportion having a wall that includes an opening therein. The wall definesinterior and exterior surfaces. The first hub portion defines aneedle-receiving channel through the opening in the wall and has asection that extends along the interior surface of the wall. The needleis mounted in the needle receiving channel and extends outwardlytherefrom. The second hub portion is engaged with the first hub portionand receives at least a portion of the needle. The second hub portionalso has reinforcing structures which extend outwardly along theexterior surface of the wall. The wall of the needle-supporting portionof the cap is reinforced on the interior surface by the first hubportion and on the exterior surface by the second hub portion.

Another aspect of the invention that relates to an automatic injector.The automatic injector comprises a housing, a cartridge, an actuationassembly, a cap, a first hub portion, a needle, and a second hubportion. The cartridge is disposed in the housing, has at least oneopening, and contains a medicament. The medicament is rearwardlyconfined by a plunger. The actuation assembly includes a stored energysource that is capable of being released to drive the plunger throughthe cartridge. The cap has an engaging portion constructed and arrangedto engage an exterior surface of the cartridge to cover the opening inthe cartridge, and a needle-supporting portion having a wall thatincludes an opening therein. The wall defines interior and exteriorsurfaces. The first hub portion defines a needle-receiving channelthrough the opening in the wall and has a section that extends along theinterior surface of the wall. The needle is mounted in the needlereceiving channel and extends outwardly therefrom. It is adapted toexpel the medicament when the plunger is driven through the chamber. Thesecond hub portion is engaged with the first hub portion and receives atleast a portion of the needle. The second hub portion also hasreinforcing structures which extend outwardly along the exterior surfaceof the wall. The wall of the needle-supporting portion of the cap isreinforced on the interior surface by the first hub portion and on theexterior surface by the second hub portion.

Yet another aspect of the invention relates to a method of forming aneedle and hub assembly. The method comprises forming a first hubportion, providing a cap having an opening therein, arranging the firsthub portion such that it has a portion thereof extending through theopening in the cap, arranging a needle in a channel defined by the firsthub portion, and forming a second hub portion over an exterior surfaceof the cap such that the second hub portion is engaged with the firsthub portion and extends over at least a portion of the exterior surfaceof the cap.

These and other aspects, features, and advantages of the invention willbecome apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in conjunction with the followingdrawing figures, in which like reference numerals designate likeelements throughout the figures, and in which:

FIG. 1 is an exploded longitudinal cross-sectional view of a cartridgefor an automatic injector having a needle and hub assembly according toone embodiment of the present invention;

FIG. 2 is a perspective view of the hub assembly of FIG. 1 in isolation;

FIG. 3 is a partially sectional perspective view of the needle and hubassembly of FIG. 1;

FIG. 4 is a longitudinal cross-sectional view of the needle and hubassembly of FIG. 1;

FIGS. 5A-5D are perspective views of the need and hub assembly of FIG. 1after each successive step of manufacture;

FIG. 6 is a high level schematic block diagram of a process formanufacturing a needle and hub assembly according to the invention;

FIG. 7 is a perspective view of an autoinjector assembly having thecartridge and needle assembly according to FIG. 1;

FIG. 8 is a partial cross section of FIG. 7 illustrating the cartridgeand needle assembly of FIG. 1; and

FIG. 9 is a perspective view of the autoinjector of FIG. 7 illustratingthe actuation assembly.

DETAILED DESCRIPTION

FIG. 1 is an exploded longitudinal cross-sectional view of a cartridgeand needle assembly generally indicated at 10, for an automatic injector1, in accordance with an embodiment of the present invention. Oneexample of the autoinjector 1 is illustrated in FIGS. 7-9. The cartridgeand needle assembly 10 is generally of the type shown and described incommonly-assigned co-pending U.S. patent application Ser. No.10/690,987, although principles, methods, and structures according tothe invention are more broadly applicable to other types of cartridgeand needle assemblies.

Typically, the cartridge and needle assembly 10 would be carried withinan outer housing 2 that includes an actuation assembly 3 having a storedenergy source 4, such as a compressed spring, shown in FIG. 9. A numberof types of automatic injector housings are known in the art, and any ofthose types may be used with the cartridge and needle assembly 10according to the present invention. As such, the present invention isnot considered to be limited solely for use with the automatic injectorillustrated in FIGS. 7-9. Furthermore, it is contemplated that theneedle assembly 14 can be used in a syringe for delivering medicament.

The cartridge 12 is of the type designed to maintain a liquid medicamentcomponent separately from a dry medicament component until activation ofthe automatic injector, at which time the two components are mixed.However, a needle and hub assembly 14 according to embodiments of theinvention may be used with a wet/dry cartridge like cartridge 12, awet/wet cartridge, or a cartridge that is designed to house aone-component liquid medicament.

The cartridge 12 is generally formed of glass, or another rigid materialthat does not react with the medicament or its components. The cartridge12 is generally cylindrical and has a smooth cylindrical inner surface.The cartridge 12 is divided into a wet medicament compartment 16 and adry medicament compartment 18. The medicament contained within the drymedicament compartment 18 may be in powder, lyophilized, or any othersolid formulation known in the art. On one end of the cartridge 12, aplunger 20 seals the liquid medicament compartment 16 and, when theactuation assembly is activated, is engaged and driven forwardly, andinto the liquid medicament compartment 16. A sealing structure 22sealingly engages the walls of the cartridge 12 to separate the liquidmedicament compartment 16 from the dry medicament compartment 18.

The sealing structure 22 is of the type disclosed and claimed incommonly-assigned U.S. patent application Ser. No. 10/690,987, thedisclosure of which specifically incorporated herein by reference.Although any type of sealing structure may be used, and if a wet/wetcartridge is used, the sealing structure 22 may take the form of arupturable membrane or another more conventional type of sealingstructure. The sealing structure 22 includes an outer sealing member 24,a moveable plug 26 secured within the outer sealing member 24, a flowpathway 28, and bypass zone 30. When the automatic injector isactivated, the advancing plunger 20 creates a pressure in the liquidmedicament compartment 16, which causes the moveable sealing plug 26 tomove forwardly within the sealing structure 22. Once the sealing plug 26has moved forwardly within the sealing structure 22, the fluid in theliquid medicament compartment 16 can enter the bypass zone 30 and mixwith the medicament component in the dry medicament compartment 18.

Methods of filling the cartridges of automatic injectors such ascartridge 12 are described in U.S. patent application Ser. No.10/690,987, and will not be repeated here in great detail. Briefly, onedifficulty with traditional filling methods is that in a two-compartmentcartridge, such as cartridge 12, if both medicament components arefilled through the same opening, cross-contamination may easily occur.That is, a powder component may inadvertently be mixed with a liquidcomponent or vice versa, especially around the opening. Therefore,especially with two-compartment cartridges, it is advantageous if thetwo components are filled through separate openings in the cartridge 12.As was noted above, it is also beneficial if the openings are relativelywide. In addition to allowing easier and faster filling of both wet andpowder medicament components, wide openings allow a dry medicamenttablet that has been lyophilized in a separate container to be placeddirectly in the dry medicament compartment 18. In the cartridge 12, thedry medicament compartment 18 has a relatively wide opening 32 locatedin the forward end of the cartridge 12, adjacent the needle and hubassembly 14.

In one filling process according to the invention, once the drycomponent is loaded into the dry medicament compartment 18, an insert 34is inserted into the opening 32. The insert 34 has a tapering flowpathway 36 and acts to funnel the mixed medicament components toward theneedle and hub assembly 14 (i.e., forwardly and inwardly) when theautomatic injector is activated. The tapered insert 34 also includes aflange portion 38 that forms a seal between the opening 32 and theneedle and hub assembly 14. In other filling processes, a needle and hubassembly may be directly sealed over the opening 32 without an insert orother directing structure within the cartridge 12. The diameter ofopening 32 may range from 0.280″ to 0.500″.

Traditionally, a needle and hub assembly for this type of cartridgewould be formed by staking a needle in an aluminum hub. Generally, a 20to 24 gauge stainless steel needle would be staked into a 0.010″ to0.015 thick aluminum extruded shell, which opens to cover an opening inthe cartridge having an outside diameter of 0.25″ to 0.30″. In the caseof an opening as wide as the opening 32 (e.g., 0.472″), it is difficultto make a traditional extruded aluminum hub that can hold the needlesecurely and attach it to the cartridge 12. In order to solve thisproblem, the needle and hub assembly 14 of the present inventionincludes both traditional extruded components and injection moldedcomponents, and is preferably made by a multi-step injection moldingprocess, as will be explained below.

Specifically, the hub and needle assembly 14 comprises a rigid cap orskirt 40, which may be formed of a metal, a first molded hub portion 42,a second molded hub portion 44, a needle 46, and a needle sheath 48. Ifthe skirt 40 is formed of a metal, it would typically be extruded,although it could also be cast or otherwise formed. Although the firstand second molded hub portions 42, 44 are described separately in someof the paragraphs below so as to facilitate description, they arepreferably fused together during manufacture and function as a singlecomponent, as will be explained. Additionally, although the skirt 40 isdescribed as being formed of a metal, it may also be formed of a plasticmaterial having sufficient rigidity.

The components of the needle and hub assembly 14 can be more clearlyseen in FIG. 4, which is a longitudinal cross-sectional view of thecomponents of the needle and hub assembly 14 in isolation, as well as inFIGS. 2 and 3, which are a perspective view and a partially sectionalperspective view, respectively, of the needle and hub assembly 14.

As is shown in the views of FIGS. 3 and 4, the skirt 40 is a generallycylindrically-shaped component of sufficient diameter to fit over theoutside of the cartridge 12 so as to close the opening 32 in the drycompartment 18. The skirt 40 has one or more hemispherical interiorprotrusions 45 that are designed to be press fit onto the surface 47,shown in FIG. 1 The lower portion 49 of the skirt 40 is rolled or pressfit into the groove 13 in the cartridge 12 in order to secure the needleand hub assembly 14 to the cartridge 12. The needle-supporting end orportion 50 of the skirt 40, which is opposite the end or portion of theskirt 40 that engages the cartridge 12, comprises a wall that is closedexcept for a central hole 52. As can be seen most clearly in FIG. 4, theneedle-supporting end 50 of the skirt 40 is essentially “sandwiched”between the first and second molded hub portions 42, 44. Thatpositioning of the needle-supporting end 50 of the skirt 40 between thefirst and second molded hub portions 42, 44 is mutually reinforcing andadds to the rigidity of the overall structure.

The first molded hub portion 42 is positioned along the interior surface50 aof the needle-supporting end 50 of the skirt 40 such that a flangeportion 54 of the first molded hub portion 42 is adjacent to theneedle-supporting end 50 of the skirt 40 and a forward portion 56 of thefirst molded hub portion extends through hole 52 in theneedle-supporting end 50 of the skirt 40. The needle 46 is mountedwithin a central channel 58 of the first molded hub portion 42 justbeyond the hole 52 in the skirt 40. The needle 46 extends to a stop 58a, shown in FIG. 4, formed in the channel 58 such that the needle can bereliably inserted to the same depth during manufacture. The stop 58alimits the insertion depth of the needle 46 within the first molded hubportion 42. Only a short length of the needle 46 is held within thefirst molded hub portion 42.

As can be seen in FIGS. 3 and 4, the first molded hub portion 42 of theillustrated embodiment defines a chamber 60 which is substantiallyhemispherical in shape. The channel 58 supporting the needle 46 opensinto the chamber 60. A filter 62 covers the wide opening of the chamber60. The chamber 60 and filter 62 are provided to direct the flow fromthe cartridge 12 toward the needle 46 and to allow for morefully-developed flow “behind” the filter 62. The particular features andadvantages of these components were described in co-pending U.S.application Ser. No. 10/690,987, of which this application is acontinuation-in-part.

It should be understood that the chamber 60 and filter 62 are optionalcomponents and need not be included in embodiments of the invention.Moreover, as will be readily understood by those skilled in the art, thefirst molded hub portion 42 may include whatever contours or structuralfeatures are necessitated by the interior arrangement of the automaticinjector with which it is designed to be used. In general, thestructural features of the first molded hub portion 42 inside of theskirt 40 are not critical to the invention, provided that the firstmolded hub portion 42 includes structures of sufficient extent to retainit in position within the skirt 40 and to reinforce the skirt 40.

The second molded hub portion 44 is disposed on the outside of theneedle-supporting end 50 of the skirt 40. It abuts the exterior surface50 bof the needle-supporting end 50 and creates a meltzone 64 where thepieces 42 and 44 are permanently joined. During formation of hub portion44, the first molded hub portion 42 is remelted so that the portions 42and 44 are joined together. As can be seen most clearly in FIGS. 2 and3, the second molded hub portion 44 includes a number of radiallyextending ribs 66 which abut the exterior surface 50 bof theneedle-supporting end 50 and extend outwardly across it. The ribs 66 actto stabilize and reinforce the needle-supporting end 50 of the skirt 40and prevent it from warping, distorting, or otherwise deforming due tothe stresses encountered during automatic injection. Contiguous with theribs 66 is a forwardly-extending tapering portion 68 which supports theneedle 46 along a greater portion of its length. Because of the firstand second molded hub portions 42, 44, the needle-supporting end 50 ofthe skirt 40 is reinforced and the needle 46 itself is well supported.

The needle assembly 14 according to the present invention is mostadvantageously manufactured using a several step injection-moldingprocess. The first and second molded hub portions 42, 44 may be made ofABS, polyethylene, polypropylene, or another well known medical gradepolymer. The injection molding process for the needle assembly 14 willbe explained below with respect to FIGS. 5A-5D, which are perspectiveviews of the needle assembly 14 at various stages of manufacture, andFIG. 6, a high-level block diagram of the steps involved in the process.Suitable injection molding apparatus for these processes is well knownin the art. One example of an appropriate injection molding apparatusthat may be used in a process according to the invention is the ArburgModel 270 All Rounder.

Manufacturing process 100 for the needle and hub assembly 14 begins atS102.Before the actual molding process begins, the user would preparethe equipment and provide appropriate mold parts for the components. Theprocess continues at S104. At S104, the user injects heated fluidplastic material into a mold component having a cavity that defines theshape of the first molded hub portion 42. The fluid plastic cools withinthe mold cavity to become the first molded hub portion 42, as shown inFIG. 5A. The hub portion 42 is then ejected from the mold. The process100 continues at S106. At S106, a needle 46 is placed in the channel 58in the first molded hub portion 42, as shown in FIG. 5B until the needle46 contacts stop 58 a. Once the needle 46 is placed in the channel 58,process 100 continues with S108, in which an extruded metal skirt 40 isplaced over the exterior of the first molded hub portion 42. Once theskirt 40 and needle 46 are in place, the assembly, which is shown inFIG. 5C, is removed from the first mold and placed in a second mold.Cavities in the second mold define the shape of the second molded hubportion. Once the assembly is in place, process 100 continues with S110,in which the second molded hub portion is overmolded onto the assembly,forming the completed needle and hub assembly 14 shown in perspective inFIG. 5D. As discussed above, during the molding of the hub portion 44, aportion of the surface area of the hub portion 42 is remelted to form amelt zone 64 such that the portions 42 and 44 are fused together to forma single piece. The process 100 ends at S112 and may be repeated as manytimes as is desired.

When the second molded hub portion 44 is overmolded in S110 of process100, the second molded hub portion 44 fuses with the first molded hubportion 42 along melt zone 64 as it cools, forming an integral, fusedcomponent. For this reason, it is typically advantageous to mold thefirst and second molded hub portions 42, 44 of the same material so thatthey can fuse together effectively. However, any two thermallycompatible materials may be used for the first and second molded hubportions 42, 44.

Process 100 also provides certain other advantages over moreconventional methods of manufacturing a needle and hub assembly. Forexample, although the components illustrated in the Figures could bemolded separately, assembled, and bonded, welded, or fit together,process 100 provides much tighter tolerances than would exist if any ofthose more conventional processes were used.

Although the invention has been described with respect to certainembodiments, those embodiments are intended to be exemplary only, andshould not be construed as limiting. Modifications and variations to theinvention as described herein may be made within the scope of theappended claims.

1. A needle and hub assembly for an injection device, the assemblycomprising: a cap having an engaging portion adapted to engage anexterior surface of a cartridge, and a needle-supporting portion havinga wall that includes an opening therein, the wall defining interior andexterior surfaces opposite each other; a first hub portion having aforward section extending through the opening in the wall and defining aneedle-receiving channel through the opening in the wall and having asection that extends along and contacts the interior surface of thewall; a needle mounted in the needle-receiving channel and extendingoutwardly therefrom; and a second hub portion mounted over the first hubportion and receiving at least a portion of the needle, the second hubportion having reinforcing structures which extend outwardly along andcontact the exterior surface of the wall, the second hub portion furtherhaving a supporting portion that extends beyond the first hub portion inthe direction of the needle and that contacts the needle; wherein thewall of the needle-supporting portion of the cap is adjoined on theexterior surface by the second hub portion and on the interior surfacedirectly opposite the adjoined exterior surface in the same direction asa longitudinal axis of the needle by the first hub portion forming acontiguous, mutually reinforcing sandwiched structure of the second hubportion, the wall, and the first hub portion that extends around theopening in the wall.
 2. The needle and hub assembly of claim 1, whereinthe first and second hub portions are fused.
 3. The needle and hubassembly of claim 2, wherein the first and second hub portions arecomprised of a plastic.
 4. The needle and hub assembly of claim 3,wherein the first and second hub portions are comprised of the sameplastic.
 5. The needle and hub assembly of claim 2, wherein the cap iscomprised of a metal.
 6. The needle and hub assembly of claim 5, whereinthe cap is comprised of aluminum.
 7. The needle and hub assembly ofclaim 1, wherein the reinforcing structures are radially-extending ribs.8. The needle and hub assembly of claim 1, wherein the needle-receivingchannel provides a continuous flow pathway from the inside of the cap tothe outside of the cap.
 9. The needle and hub assembly of claim 1wherein the needle-receiving channel has a stop formed therein to limitthe insertion depth of the needle within the first hub portion.
 10. Anautomatic injector comprising: a housing; a cartridge disposed in thehousing, the cartridge having at least one opening therein andcontaining a medicament, the medicament being rearwardly confined by aplunger; an actuation assembly including a stored energy source that iscapable of being released to drive the plunger through the cartridge; acap having an engaging portion adapted to engage an exterior surface ofthe cartridge to cover the opening in the cartridge, and aneedle-supporting portion having a wall that includes an openingtherein, the wall defining interior and exterior surfaces opposite eachother; a first hub portion having a forward section extending throughthe opening in the wall and defining a needle-receiving channel throughthe opening in the wall and having a section that extends along andcontacts the interior surface of the wall; a needle mounted in theneedle-receiving channel and extending outwardly therefrom, the needleoperative to expel the medicament when the plunger is driven through thecartridge; and a second hub portion engaged with the first hub portionand receiving at least a portion of the needle, the second hub portionhaving reinforcing structures which extend outwardly along and contactthe exterior surface of the wall directly opposite, and in the samedirection as a longitudinal axis of the needle, the interior surface ofthe wall contacted by the first hub portion, the second hub portionfurther having a supporting portion that extends beyond the first hubportion in the direction of the needle and that contacts the needle;wherein the reinforcing structures are radially-extending ribs, and thesecond hub portion, the wall, and the first hub portion form acontiguous, mutually reinforcing sandwiched structure that extendsaround the opening in the wall.
 11. The automatic injector of claim 10,wherein the first and second hub portions are fused.
 12. The automaticinjector of claim 11, wherein the first and second hub portions arecomprised of a plastic.
 13. The automatic injector of claim 12, whereinthe first and second hub portions are comprised of the same plastic. 14.The automatic injector of claim 10, wherein the cap is comprised of ametal.
 15. The automatic injector of claim 14, wherein the cap iscomprised of aluminum.
 16. The automatic injector of claim 10, whereinthe first hub portion defines a chamber into which the needle-receivingchannel opens.
 17. The automatic injector of claim 10, wherein theneedle-receiving channel provides a continuous flow pathway from theinside of the cap to the outside of the cap.
 18. The automatic injectorof claim 10, wherein the cartridge has two medicament compartments. 19.The automatic injector of claim 18, wherein one of the medicamentcompartments is adapted to house a wet medicament component and theother medicament compartment is adapted to house a dry medicamentcomponent.
 20. The automatic injector of claim 19, wherein the at leastone opening in the cartridge is in the dry medicament compartment. 21.The automatic injector of claim 10 wherein the needle-receiving channelhas a stop formed therein to limit the insertion depth of the needlewithin the first hub portion.